A Failure Model for Equipments Undergoing Complex Operation

Abstract

A simple failure model for equipment undergoing several cycles of operation is given by the expression, 1 − exp(−Λ∑ ı =1 ı = k τ i ), where Λ is the failure coefficient, τ i is the length of the ı th cycle of operation, and k is the number of cycles. A consequence of this model is that the probability of failure for a given total operating time is independent of the number of cycles of operation. It is shown that, under certain assumptions, a failure model that takes account of the number of cycles of operation, as well as the operating time, is given by the expression, 1 − exp(Λ 0 ∑ ı =1 ı = k τ ı + Λ 1 k ). Interpretations of the constants, Λ 0 and Λ 1 , are given. Also discussed is a method for testing the plausibility of the model against failure data.